Data communication apparatus and data communication method

ABSTRACT

Realizing a data communication device and a data communication method enabling to specify an IC memory mounted in the communication device and to perform data communication to the communication device in which the IC memory is mounted. 
     A mobile device  100  of transmitting side accepts a domain ID specifying a detachable IC memory uniquely from an application  102 , a communication driver  105  obtains an IP address of the device of correspondent on the basis of the accepted domain ID from a name server  300  storing the domain ID and the IP address being associated with each other. Then, the communication driver  105  obtains a port ID which an IC memory of the device of correspondent assigned to an application, and transmits the domain ID and the port ID together with a transmission data to the IP address. The device of correspondent rims the application based on the received port ID and executes an appropriate processing.

TECHNICAL FIELD

The present invention relates to a data communication device and a datacommunication method capable of transmitting data addressed to aspecific IC memory.

BACKGROUND ART

In a conventional communication method, an application running on adevice as a communicator has communicated with an application of thedevice of correspondent. For example, an application of an electronicmail and the like may specify the device of correspondent using ane-mail address to send an e-mail to an e-mail application (or a mailserver) which is to be the device of correspondent via the Internet, LAN(Local Area Network), and the like.

Further, as an invention that a memory card is mountable, the inventiondescribed in the Patent Document 1 can be listed, which describeswriting/reading a mail data to/from a memory card.

-   [Patent Document 1] Japanese Patent Application Laid-open No.    2001-84194

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

A communication device on which a memory card such as an IC memory canbe mounted detachably exists as described in the Patent Document 1,however, the memory card described in the Patent Document 1 is used onlyfor writing/reading data thereto/therefrom. Therefore, it covers a datatransmission addressed to a communication device, which does notconsider the case where desiring a transmission addressed to acommunication device on which a specific IC memory is mounted.

Recently, however, there may be a case where a transmission addressed toa communication device on which a specific detachable IC memory ismounted is desired. For example, when using a communication device onwhich electronic money application is installed, there may be a casewhere a user desires to draw/remit electronic money data registered inthe IC memory, and therefore, there may be a case where the user desiresto carry around only the IC memory when going out and insert the ICmemory into a communication device palaced at a place where the user isstaying to execute transactions of electronic money by using thecommunication device. In this case, it is necessary to specify the ICmemory to transmit and receive the data, rather than specify thecommunication device to deal.

So far, a communication device per se has been specified as adestination, which made it impossible to transmit data addressed to anIC memory mounted on the communication device, and therefore, realizingthe electronic money application has been difficult.

Therefore, the object of the present invention is to realize a datacommunication device and a data communication method enabling to specifyan IC memory mounted on a communication device and to transmit data tothe communication device on which the IC memory is mounted.

Means for Solving the Problem

To solve the problem, a data communication device according to thepresent invention comprises: an accepting means for accepting a domainID specifying a detachable IC memory uniquely; a destination informationobtaining means for obtaining a destination information of the device ofcorrespondent from a server by transmitting the domain ID accepted bythe accepting means to the server storing the domain ID and thedestination information being associated with each other; a port IDobtaining means for transmitting information specifying a type ofapplication to the device of correspondent having the destinationinformation obtained by the destination information obtaining means toobtain a port ID which an IC memory of the device of correspondentassigned to the same type of application as that of the application; anda transmission means for transmitting the domain ID accepted by theaccepting means and the port ID obtained by the port ID obtaining meanstogether with a transmission data to the destination indicated by thedestination information obtained by the destination informationobtaining means.

Further, a data communication method according to the present inventioncomprises: an accepting step of accepting a domain ID specifying adetachable IC memory uniquely; a destination information obtaining stepof obtaining an destination information of the device of correspondentcorresponding to the accepted domain ID from a server by transmittingthe accepted domain ID to the server storing the domain ID and thedestination information being associated with each other; a port IDobtaining step of transmitting information specifying a type ofapplication to the device of correspondent having the obtaineddestination information to obtain a port ID which an IC memory of thedevice of correspondent assigned to the same type of application as thatof the application; and a transmission step of transmitting the accepteddomain ID and the obtained port ID together with a transmission data tothe destination indicated by the destination information obtained in thedestination information obtaining step.

According to the configuration of the present invention, retrieving thedestination information corresponding to the domain ID of thedestination to which a transmission is desired to be made from theserver storing the domain ID specifying the IC memory uniquely inrelationship to the destination information, retrieving the port ID onthe basis of the information specifying the type of application from thedevice of correspondent of the retrieved destination information, andtransmitting the retrieved domain ID capable of specifying the IC memoryand the port ID assigned by the IC memory, together with a data, make itpossible to communicate with the communication device on which the ICmemory is mounted by specifying the IC memory per se without executing acomplicated management even if the IC memory is mounted on the otherdevice.

A data communication device according to the present invention furthercomprises: a key obtaining means for obtaining a public keycorresponding to the domain ID accepted by the accepting means; and anencryption means for encrypting a transmission data to be transmitted bythe transmission means using the public key obtained by the keyobtaining means; wherein the transmission means transmits thetransmission data encrypted by the encryption means.

According to the configuration of the present invention, a data to betransmitted is encrypted with the public key corresponding to the domainID, which improves the confidentiality of communication.

Further, a data communication device according to the present inventionfurther comprises: a digital signature means for attaching a digitalsignature to the transmission data to be transmitted by the transmissionmeans, wherein the transmission means transmits the transmission data towhich an electronic signature is attached by the digital signaturemeans.

According to the configuration of the present invention, attaching thedigital signature to the data to be transmitted is able to vouch for thevalidity thereof.

Further, a data communication device according to the present inventioncomprises: a detachable IC memory storing a domain ID capable ofspecifying the IC memory uniquely, and assigning a port ID in responseto a request for assigning the port ID from an application, and storinginformation specifying a type of the assigned application inrelationship to the assigned port ID; a registration means forregistering the domain ID specifying the IC memory uniquely when the ICmemory is mounted therein, in relationship to a destination informationof the device body, in a server placed in a network; a receiving meansfor receiving information specifying a type of application running onthe device of correspondent from the device of correspondenttransmitting data with the IC memory as its destination; a retrievingmeans for retrieving from the IC memory a port ID corresponding to theinformation specifying the type of application received by the receivingmeans; and a transmission means for transmitting the port ID retrievedby the retrieving means to the device of correspondent.

Further, a data communication method according to the present inventioncomprises: a registration step of, when an IC memory is mounted,registering in a server placed in a network, a domain ID capable ofspecifying the IC memory uniquely in relationship to a destinationinformation of a device body in which the IC memory is mounted, afterthe registration step, in the IC memory, an assigning step of assigninga port ID in response to a request for assigning the port ID from anapplication and a storing step of storing information specifying a typeof the assigned application in relationship to the assigned port ID; areceiving step of receiving information specifying a type of applicationrunning on the device of correspondent from the device of correspondenttransmitting data with the IC memory as its destination; a retrievingstep of retrieving from the IC memory a port ID corresponding to thereceived information specifying the type of application; and atransmission step of transmitting the retrieved port ID to the device ofcorrespondent.

According to the configuration of the present invention, assigning theport ID to each application, and informing the port ID in response to arequest from the device of correspondent, make it possible that thedevice of correspondent obtains the port ID corresponding to theapplication running on the device of correspondent side, the device ofcorrespondent transmits data addressed to the obtained port ID, andcommunicates with the communication device having an IC memory byspecifying the IC memory per se without executing a complicatedmanagement even if the IC memory is mounted on the other device.

Further, a data communication device according to the present inventioncomprises: an accepting means for accepting a domain ID specifying adetachable IC memory uniquely; an obtaining means for transmitting thedomain ID accepted by the accepting means and information specifying atype of application with the broadcast to obtain a destinationinformation corresponding to the transmitted domain ID and a port IDcorresponding to the transmitted information specifying the type ofapplication from a device in a network corresponding to the domain IDtransmitted with the broadcast; and a transmission means fortransmitting the domain ID accepted by the accepting means and the portID obtained by the obtaining means together with a transmission data tothe destination indicated by the destination information obtained by theobtaining means.

Further, a data communication method according to the present inventioncomprises: an accepting step of accepting a domain ID specifying adetachable IC memory uniquely; a broadcast-transmission step oftransmitting the accepted domain ID and information specifying a type ofapplication with the broadcast; an obtaining step of obtaining adestination information corresponding to the transmitted domain ID and aport ID corresponding to the transmitted information specifying a typeof application from a device in a network having the same domain ID asthat transmitted with the broadcast; and a data transmission step oftransmitting the domain ID accepted in the accepting step and the portID obtained in the obtaining step together with a transmission data tothe destination indicated by the obtained destination information.

According to the configuration of the present invention, transmittingwith the broadcast the accepted domain ID and the information specifyinga type of application and receiving a response of the port ID from thedevice having the same domain ID do not necessitate the name serverstoring the domain ID in relationship to the destination information andmake it possible to obtain the destination information and the port IDof the other side and to transmit by specifying the detachable devicesuch as an IC memory uniquely, without the processing of registering inthe name server.

Effect of the Invention

According to the present invention, retrieving the destinationinformation corresponding to the domain ID of the destination to which atransmission is desired to be made, from the server storing the domainID specifying the IC memory uniquely in relationship to the destinationinformation, retrieving the port ID on the basis of the informationspecifying the type of application from the device of correspondent ofthe retrieved destination information, and transmitting the retrieveddomain ID capable of specifying the IC memory and the port ID assignedby the IC memory, together with a data make it possible to communicatewith the communication device on which the IC memory is mounted byspecifying the IC memory per se without executing a complicatedmanagement even if the IC memory is mounted on the other device.

Further, according to the present invention, assigning the port ID toeach application, and informing the port ID in response to a requestfrom the device of correspondent make it possible that the device ofcorrespondent obtains the port ID corresponding to the applicationrunning on the device of correspondent, transmits data addressed to theobtained port ID, and communicates with the communication device havingthe IC memory by specifying the IC memory per se without executing acomplicated management even if the IC memory is mounted on the otherdevice.

Further, according to the present invention, transmitting with thebroadcast the accepted domain ID and the information specifying a typeof application and receiving a response of the port ID from the devicehaving the same domain ID do not necessitate the name server storing thedomain ID in relationship to the destination information and make itpossible to obtain the destination information and the port ID of thedevice of correspondent and to transmit by specifying the detachabledevice such as an IC memory uniquely, without the processing ofregistering in the name server.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a network system configuration diagram in which a mobiledevice 100 of the present invention is used.

FIG. 2 is a block diagram of the mobile device 100 and a mobile device200 of the present invention.

FIG. 3 is a schematic diagram explaining eTRON ID used by the mobiledevice 100 of the present invention.

FIG. 4 is a sequence diagram showing a communication processing betweenthe mobile device 100 and the mobile device 200 of the presentinvention.

FIG. 5 is a block diagram of a mobile device 100 a executing anencryption processing, and a mobile device 200 a executing a decryptionprocessing of the present invention.

FIG. 6 is a sequence diagram showing a communication processing betweenthe mobile device 100 a and the mobile device 200 a of the presentinvention.

FIG. 7 is a block diagram of a mobile device 100 b executing a broadcastprocessing and a mobile device 200 b receiving a broadcast, of thepresent invention.

FIG. 8 is a sequence diagram showing a communication processing betweenthe mobile device 100 b and the mobile device 200 b of the presentinvention.

EXPLANATION OF REFERENCE NUMERALS

-   -   100, 200 mobile device

-   101, 201 IC memory

-   102, 202 application

-   103, 203 IC memory driver

-   104, 204 domain ID registration section

-   105, 205 communication driver

-   106, 206 communication section

BEST MODE FOR CARRYING OUT THE INVENTION

A data communication device and a data communication method according tothe present invention will now be explained referring to the drawings.Firstly, the outline of the present application will be described. FIG.1 is a system diagram showing the data communication device of thepresent invention in which a mobile device 100 is used. As shown in FIG.1, the mobile device 100 is capable of communicating with a mobiledevice 200 that is the device of correspondent, via a radio network. Themobile device 100 and the mobile device 200 may be detachably providedwith an IC memory 101 and an IC memory 201 respectively. Even if the ICmemory 201 is removed from the mobile device 200 to be mounted on theother mobile device, the mobile device 100 is able to specify on whichmobile device the IC memory 201 is mounted using a name server 300.

Next, the processing of specifying the IC memory 201 mounted on themobile device 200 executed in the mobile device 100 will be explained.FIG. 2 is a block diagram of the mobile device 100.

The mobile device 100 is provided with an IC memory 101, an application102 (an accepting means and a digital signature means of the presentinvention), an IC memory driver 103, a domain ID registration section104, a communication driver 105 (an address information obtaining means,a port ID obtaining means, and a transmission means of the presentinvention), a communication section 106 (a transmission means of thepresent invention), and an address book 107.

The IC memory 101 is storing a pre-assigned domain ID capable ofspecifying the IC memory uniquely, further detachably provided for themobile device 100, and storing various types of data. In thisembodiment, it is assumed to be able to store electronic money data.Moreover, it has a function of assigning a port ID capable of specifyingan application uniquely in response to a request from the application.

The application 102 is one which is capable of running on the mobiledevice, and it is assumed to be an application for performing anelectronic payment processing in the present invention. Also theapplication 102 may accept the domain ID capable of specifying (the ICmemory of) the device of correspondent uniquely with a user's inputoperation, issue a bill to the device of correspondent, and registerelectronic money data received from the correspondent in the IC memory101.

The IC memory driver 103 is a driver software for performing a dataaccess to the IC memory in response to a request from the application102. The IC memory driver 103 executes a processing of registration anddrawing the electronic money to the IC memory 101 according to theinstruction of the application 102. Further, when detecting that the ICmemory 101 is mounted, it retrieves the domain ID registered in the ICmemory 101 to pass it to the domain ID registration section 104described later.

The domain ID registration section 104 accepts the domain ID from the ICmemory driver 103 to execute a processing of registering it in the nameserver 300. The registration processing is executed via thecommunication driver 105 described later.

The domain ID registered here is a part of eTRON ID. The particularsthereof are shown in the drawing. FIG. 3 is a detailed drawing of eTRONID composed of domain ID and port ID,

As shown in FIG. 3, eTRON ID consists of 12 bytes of domain ID and 4bytes of port ID. The domain ID is an ID specifying a device such as anIC memory. The port ID is an ID which a device such as an IC memoryassigns to an application when the application using the device isactivated. The data communication device according to the presentinvention is capable of communicating with the domain ID and port ID asa destination.

Further, the domain ID registration section 104 retrieves an IP addresswhich is an address of the name server and an IP address of the mobiledevice 100 from the memory preliminary storing these IP addressestherein to output them to the communication driver 105 described later.In addition, a telephone number and an e-mail address instead of the IPaddress may be output to the communication driver 105 as destinationinformation.

The communication driver 105 is a driver software controlling acommunication section 106, executes a processing of registering the IPaddress of the mobile device 100 (own device) retrieved and output fromthe domain ID registration section 104, and the domain ID retrieved fromthe IC memory 101 addressed to the IP address of the name server 300obtained at the domain ID registration section 104. Further, whendesiring to obtain an IP address of the device of correspondent, thecommunication driver 105 transmits a domain ID of the device ofcorrespondent to the name server 300 to obtain IP address of the deviceof correspondent corresponding to the domain ID. Moreover, bytransmitting a request for obtaining the port ID and informationspecifying a type of application running in the mobile device 100 to themobile device 200 as the device of correspondent, the communicationdriver 105 retrieves the port ID assigned to the same type ofapplication as the transmitted information specifying the type ofapplication in the mobile device 200. Further, it executes theprocessing of receiving the electronic money data from the mobile device200 to pass it to the application 102. In addition, a telephone numberand an e-mail address instead of the IP address may be the destinationinformation.

The communication section 106 has a function of connecting with the nameserver 300 and an external network.

The address book 107 is composed of a memory storing the domain ID ofthe device of correspondent, and the address book 107 is able to outputthe registered domain IDs to the application 102 in response to itsrequest, making the application 102 display the listing thereof so thatthey may be input selectively. This address book 107 is generated by auser's preliminary registration processing.

The block diagram of the mobile device 100 has been explained above, andthe mobile device 200 is also configured to comprise an IC memory 201(IC memory of the present invention), an IC memory driver 203 (anobtaining means of the present invention), a domain ID registrationsection 204 (a registration means of the present invention), acommunication driver 205 (receiver and transmission means of the presentinvention) and a communication section 206 (receiver and transmissionmeans of the present invention).

The IC memory 201 is preliminary assigned the domain ID, storing theassigned domain ID. It also assigns the predetermined port ID to theapplication 202 in response to a request of the application 202. Theassigned port ID is uniquely assigned and managed by the IC memory 201in such a manner that the same one does not exist. Further, it storesthe assigned port ID in relationship to information specifying the typeof application (a label of application (a category such as anapplication handling electronic money, an application handling anelectronic ticket, and an application handling an electronicsignature)).

The application 202 starts up, and then, makes a request for assigningthe port ID to the IC memory 201 as described above. Further, onstarting up according to the instruction from the communication driver205, it may execute the processing of drawing the electronic money formthe IC memory 201. Also when receiving the bill, it may draw theelectronic money data from the IC memory 101 to transmit the data to thedevice of correspondent.

The communication driver 205 instructs the IC memory driver 203 toretrieve the port ID from the IC memory 201 when receiving a request forobtaining the port ID from the mobile device 100. The IC memory driver203 retrieves the port ID from the IC memory 201 to pass it to thecommunication driver 205. Further, when receiving a message M and a portID which are the data transmitted from the mobile device 100, thecommunication driver 205 activates the application corresponding to theport ID. Further, it transmits the data (electronic money data) receivedfrom the IC memory 201 to the mobile device 100 via the application 202.

The other configuration of the mobile device 200 operates in the samemanner as the mobile device 100.

Next, the detailed processing to be executed when the mobile device 100configured above executes a processing of payment with electronic moneyto the IC memory mounted on the mobile device 200 will be explained.FIG. 4 is a sequence diagram thereof.

In the mobile device 100, when the IC memory 101 is mounted, the ICmemory driver 103 detects this, retrieves the domain ID preliminaryregistered in the IC memory 101 and outputs the retrieved domain ID tothe domain ID registration section 104. The domain ID registrationsection 104 outputs the received domain ID, the IP address of the mobiledevice 100 together with the IP address as a destination of the nameserver 300 to the communication driver 105. The communication driver 105transmits the domain ID and the IP address of the mobile device 100being associated with each other addressed to the name server 300, wherethe domain ID and the IP address of the mobile device 100 are registeredbeing associated with each other (S401 a). In the mobile device 200, thesame registration processing is executed (S401 b).

In the mobile device 200, the activated application 202 makes a requestfor assigning a port ID to the memory 201. The IC memory 201 assigns aport ID to the activated application 202 (S402 b), and stores theassigned port ID in relationship to information specifying the assignedapplication 202 (a label of application (a category such as anapplication handling electronic money, an application handling anelectronic ticket, an application handling an electronic signature))(S403 b).

Thus, different types of information are registered in the name server300, and in the mobile device 200, the port ID of the application 202 isassigned. A user utilizing the mobile device 100 (IC memory 101) isinformed of only the domain ID by a user utilizing the IC memory 201,and the informed domain ID is registered in the address book 107.

The mobile device 100 operates an application for the electronic paymentprocessing and outputs a message M which is a bill data together withthe domain ID of the IC memory 201 mounted on the mobile device 200 tothe communication driver 105 in order to execute a processing oftransmitting the bill data to the mobile device 200 (S404 a).

The communication driver 105 transmits the domain ID of the IC memory ofthe mobile device 200 to the name server 300 to obtain the IP addresscorresponding to the transmitted domain ID. Namely, the name server 300retrieves the IP address stored therein being associated with the domainID after receiving the domain ID from the mobile device 100, and repliesthe retrieved IP address to the mobile 100 (S405 a).

The communication driver 105 requests for retrieving the port IDaddressed to the IP address received from the name server 300 (S406 a).This request includes information specifying a type of applicationrunning in the mobile device 100, for example, information specifying alabel of application as well as information indicating a category suchas an application handling electronic money, an application handling anelectronic ticket, and an application handling an electronic signature.

The communication driver 205 of the mobile device 200 that receives thisrequest, outputs the information specifying a type of applicationrunning in the mobile device 100 to the IC memory driver 203. The ICmemory driver 203 retrieves the corresponding port ID from the IC memoryon the basis of the information specifying the type of the specificapplication running in the mobile device 200. Then, the IC memory driver203 outputs the retrieved port ID to the communication driver 205 (S407b). The communication driver 205 transmits the port ID to the mobiledevice 100 (S408 b). It is assumed here that, the same label (category)of application may perform the same processing such as handlingelectronic money, handing an electronic ticket, and handling anelectronic signature without regard to the identity of the application.

The communication driver 105 of the mobile device 100 transmits as a setof the received port ID, accepted domain ID and the message M which isthe bill data to be transmitted addressed to the mobile device 200 (S409a).

The communication driver 205 of the mobile device 200 calls anapplication corresponding to the port ID to be activate. The application202 is assumed here to perform an electronic payment processing. Whenthe application 202 judges that the bill data has been transmitted, theapplication 202 recognizes the amount of money described in the billdata, and detects the domain ID transmitted as the destination to judgethat the transmission has been made addressed to the IC memory. Then,the application 202 instructs the IC memory driver 203 to draw theamount of electronic money from the IC memory 201. The IC memory driver203 executes the processing of drawing the amount of electronic moneydescribed in the bill data from the IC memory 201 and outputs this tothe application 202. The application 202 instructs the communicationdriver 205 to transmit the electronic money data to the mobile device100 (S410 b). The communication driver 205 transmits the electronicmoney data to the mobile device 100 (S411 b).

The communication driver 105 of the mobile device 100 receives theelectronic money data and outputs this to the application 102. Theapplication 102 detects that the electronic money data has been receivedand instructs the IC memory driver 103 to execute the processing ofadding the electronic money data to the IC memory 101. The IC memorydriver 103 executes a summing processing (S412 a).

In addition, in the application 102, attaching a digital signature tothe massage M to be transmitted may vouch for the validity of themessage M. Specifically, the application 102 attaches the predeterminedsignature to the message M and encrypts the signature by using a secretkey owned by a sending side to transmit. The receiving side decrypts thesignature using a signatory's public key. If decrypted correctly, thereceipt of the data that is correct may be confirmed.

The effect of the present invention described above will be explainedbelow. Transmitting the domain ID capable of specifying the IC memoryand the port ID assigned by the IC memory, together with a data makes itpossible to communicate with the communication device on which the ICmemory is mounted by specifying the IC memory per se without executing acomplicated management even if the IC memory is mounted on the otherdevice.

Subsequently, the processing executed when encrypting the bill data tobe transmitted using the public key corresponding to the domain ID willbe explained.

FIG. 5 is a block diagram of mobile devices 100 a and 200 a executing anencryption processing. The mobile devices 100 a and 200 a shown in thisdrawing have the following function in addition to the configurationexplained referring to FIG. 2 described above.

The mobile device 100 a of the present invention comprises an IC memory101 a (an encryption means of the present invention), an application 102a, an IC memory driver 103, a domain ID registration section 104, acommunication driver 105 a (a key obtaining means of the presentinvention), and a communication section 106, and further, the mobiledevice 200 a comprises an IC memory 201 a, an application 202 a, an ICmemory driver 203, a domain ID registration section 204, a communicationdriver 205, and a communication section 206.

The application 102 a has a function of asking for encryption to the ICmemory 101 a when transmitting the bill data consisting of the messageM.

The communication driver 105 a has a function of accessing to a keyserver to obtain the public key corresponding to a domain ID of thecommunication destination, after receiving an encryption request fromthe application 102 a. The IC memory 101 a encrypts the bill data whichis the message M to be transmitted using the obtained public key togenerate the bill data which becomes a message C.

The application 202 a of the mobile device 200 a makes the IC memory 201a execute a decryption processing via the IC memory driver 203 afterreceiving the encrypted message C.

The IC memory 201 a executes the decryption processing of the message Cusing a preliminary holding secret key to generate the message M.

The processing and operation thereof will be hereafter explained. FIG. 6is a sequence diagram of the processing. It is assumed here that theprocessing of registering the domain ID shown in FIG. 4 (S401 a, etc.)and the processing of assigning the port ID (S402 b), or the like arealready executed.

Firstly, the application 102 a transmits to ask for a processing ofissuing the bill data, accepts the domain ID, and outputs the accepteddomain ID to the communication driver 105 a (S501 a). The communicationdriver 105 a accepts this, outputs the domain ID to the name server 300,and obtains the corresponding IP address from the name server 300 (S502a). The name server 300 is configured in the same manner as describedabove.

The communication driver 105 a requests for retrieving the port IDaddressed to the IP address received from the name server 300 (S503 a).This request includes information specifying a type of applicationrunning in the mobile device 100, such as a label of application (acategory such as an application handling electronic money, anapplication handling an electronic ticket, an application handling anelectronic signature).

The communication driver 205 of the mobile device 200 a that receivesthis request, outputs the information specifying a type of applicationto the IC memory driver 203. The IC memory driver 203 retrieves thecorresponding port ID from the IC memory 201 a on the basis of theinformation specifying the type of the application. Then, the IC memorydriver 203 outputs the retrieved port ID to the communication driver 205(S504 b). The communication driver 205 transmits the port ID to themobile device 100 (S505 b).

After the communication driver 105 receives the port ID, the application102 a outputs the message M and the domain ID of the IC memory 201 whichis mounted on the mobile device 200 that is the destination, to the ICmemory driver 105 to ask for the encryption processing of the message Mwhich is the bill data to the IC memory 101. The IC memory driver 105instructs the communication driver 105 a to retrieve the public key forencryption from the key server. The communication driver 105 a transmitsthe domain ID to the key server and retrieves the corresponding publickey to the mobile device 100 a from the key server storing the publickey corresponding to the domain ID. Then, the communication driver 105 aoutputs the public key obtained here to the IC memory 101 a via the ICmemory driver 103. The IC memory 101 a executes the encryptionprocessing using the public key. Subsequently, the message M isencrypted as the message C, and the IC memory driver 103 retrieves themessage C from the IC memory 101 a and outputs to the communicationdriver 105 a (S506 a).

The communication driver 105 a transmits the received message C togetherwith the domain ID of the IC memory 201 and the port ID to the mobiledevice 200 a the destination of which is the IP address (S507 a).

The communication driver 205 of the mobile device 200 receives the portID and activates the application 202 a corresponding the port ID. Whenthe application 202 a detects the message C, the application 202 ajudges it to be an encrypted message, and outputs it to the IC memory201 a via the IC memory driver 203 for decryption. The IC memory 201 astores the private key corresponding to the public key used for theencryption, and decrypts the message C using the private key. Themessage M obtained by the decryption is output to the application 202 avia the IC memory driver 103 (S508 b).

The application 202 a detects the message M and recognizes it as thebill data, instructing the IC memory driver 203 to execute the drawingprocessing. The IC memory driver 203 executes the processing of drawingto the IC memory 201 a to retrieve the electronic money data from the ICmemory 201 a, and outputs it to the communication driver 205 via theapplication 202 a (S509 b). The communication driver 205 transmits thereceived electronic money data to the mobile device 100 (S510 b).

The communication driver 105 a of the mobile device 100 a receives theelectronic money data, and outputs it to the application 102 a. When theapplication 102 a detects that the electronic money data has beenreceived, it instructs the IC memory driver 103 to execute theprocessing of adding the electronic money data to the IC memory 101 a,and the IC memory driver 103 executes the summing processing (S511 a).

The effect of the present invention executing the encryption describedabove will be explained. In addition to the effect of the inventiondescribed above referring to FIG. 2, by encrypting the message M whichis a data to be transmitted with the public key corresponding to thedomain ID, the confidentiality of communication may be improved.

Next, the method of executing a transmission processing with a broadcastand obtaining a port ID will be explained. FIG. 7 is a block diagram ofdata communication devices 100 b and 200 b executing the transmissionprocessing with the broadcast.

The mobile device 100 b is provided with an IC memory 101, anapplication 102 b (an accepting means of the present invention), an ICmemory driver 103, a communication driver 105 b (an obtaining means,transmitting means of the present invention), a communication section106 (a transmitting means of the present invention), and an address book107, and the mobile device 200 b is provided with an IC memory 201, anapplication 202, an IC memory driver 203, a communication driver 205 b,a communication section 206 and an address book 107.

The communication driver 105 b receives a transmission request from theapplication 102 b, and then transmits the domain ID accepted on the sideof the application 102 b and information specifying a type of theapplication addressed to an unspecified number of terminals in anetwork. The domain ID is transmitted, as we say, with the broadcast.When the communication driver 205 b of the mobile device 200 b that isthe device of correspondent and that received the domain ID that hasbeen transmitted with the broadcast, recognizes the domain ID as its owndomain ID, it returns the IP address and the port ID of the mobiledevice 200 b to the sender (mobile device 100 b) of the broadcasttransmission.

In this embodiment the IP address may be obtained with the broadcast,which eliminates the necessity of storing the domain ID in relationshipto the IP address in the name server, and does not necessitate thedomain ID registration section, however, the other configuration andfunction are the same as those explained referring to FIG. 2.

FIG. 8 is a sequence diagram showing the processing thereof Theapplication 102 b accepts the domain ID of the device of correspondentby input operation of a user and requests for transmission (S801 a). Thecommunication driver 105 b then transmits the accepted domain ID and theinformation specifying the running application 102 b over the networkwith the broadcast (S802 b). The mobile device 200 b which is a mobiledevice corresponding to the domain ID, recognizes domain ID delivered bythe broadcast as its own one, and then retrieves the corresponding portID on the basis of the information specifying a type of application andreturns the port ID together with the IP address of the mobile device200 b to the sender (mobile device 100 b) which performed broadcasttransmission (S803 b).

The communication driver 105 b which received the IP address and theport ID transmits the message M, the domain ID and the port ID to themobile device 200 b, the destination of which is the received IP address(S804 a). On receiving this, the mobile device 200 b recognizes the portID and activates the corresponding application (S805 b). Thereafter, themobile devices 100 b and 200 b will perform the same procedures (S410 b,S411 b, S412 a) as those shown in FIG. 4 (not shown in the figure).

The effect of the present invention described above will be explained.Transmission of the accepted domain ID and the information specifying atype of application with a broadcast does not necessitate the nameserver storing the domain ID in relationship to the destinationinformation such as an IP address and makes it possible to obtain thedestination information such as an IP address and the port ID of theother device and to transmit by specifying the detachable device such asan IC memory uniquely, without the processing of registering in the nameserver.

The invention claimed is:
 1. A data communication device comprising: a detachable IC memory attached to the data communication device and configured to store a unique domain ID uniquely assigned to the detachable IC memory, the detachable IC memory uniquely assigning a port ID in response to a port ID request from an application, the detachable IC memory storing information specifying the application to which the port ID is assigned in association with the assigned port ID; a registration section configured to register the unique domain ID uniquely assigned to the detachable IC memory when the IC memory is mounted therein, the unique domain ID being registered in a server connected to a network, in relationship to a destination information of the data communication device; a communication section configured to receive information specifying an application running on a correspondent device, the correspondent device transmitting data to the detachable IC memory; and a retrieving driver configured to retrieve from the detachable IC memory a port ID corresponding to the information specifying the application, wherein the communication section transmits the port ID the correspondent device, and the application to which the port ID is assigned and the application running on the correspondent device perform money transactions, and the data transmitted by the correspondent device is electronic money data.
 2. A data communication method comprising: registering, in a server placed in a network, a unique domain ID uniquely assigned to an IC memory when the IC memory is mounted on a data communication device, the unique domain ID being registered in relationship to a destination information of the data communication device in which the IC memory is mounted, uniquely assigning, in the IC memory, a port ID in response to a port ID request from an application and storing information specifying the assigned application in relationship to the assigned port ID; receiving information specifying an application running on a correspondent, device the correspondent device transmitting data to the IC memory; retrieving, from the IC memory, a port ID corresponding to the received information specifying the application; and transmitting the retrieved port ID to the correspondent device, wherein the application to which the port ID is assigned and the application running on the correspondent device perform money transactions, and the data transmitted by the correspondent device is electronic money data. 